Remove the favas from their pods and shell the peas
Bring a large pot of water with 2 teaspoons salt to a boil. Prepare an ice bath by adding a generous amount of ice to a medium bowl of water. Add the favas to the boiling water and cook for 2 minutes (if the favas are small) or 3 minutes (if they are large). Remove the favas with a fine-mesh strainer (reserving the water in the pot) and transfer to the ice water. Let sit for a minute or 2. Bring the water in the pot back to a boil and add the peas. Cook for 1 minute and use the fine-mesh strainer to transfer the peas to a folded dishtowel or a few layers of paper towels. Keep the pot on the stove.
Remove the favas from the ice water and remove the outer coating of each fava by pinching the stem end of the bean with your thumbnail and popping or slipping the bean out of the skin.
Bring the pot of water back to a boil and add the angel hair. Cook, stirring, for about 45 seconds, or according to the package instructions. Reserve some of the cooking water and transfer the angel hair to a strainer in the sink.
In a large (12-inch) nonstick skillet, arrange the pancetta slices over medium heat. Cook until crisp and browned, about 5 minutes. Transfer to a paper towel–lined plate. When cool, crumble and set aside.
Add 2 tablespoons of the butter to the skillet. When melted, add the sliced shallots and a pinch of salt, and cook, stirring, until the shallots are softened and lightly browned, 4 to 5 minutes. Add the favas and the peas to the pan, season with a pinch of salt, and cook, stirring, just until the veggies are heated through, 1 to 2 minutes. Turn the heat to low. Add the remaining 1 tablespoon butter, the lemon zest, a few tablespoons of the pasta water, the cooked pasta, half of the Parmigiano, half of the mint, a pinch of salt, and several grinds of black pepper. Stir and toss until all the ingredients are mixed together as thoroughly as possible (the veggies will roll around a bit!), adding a little more pasta water if needed to loosen the mixture. Squeeze a small bit of lemon over all. Remove the pan from the heat and transfer to serving bowls. Garnish with the remaining mint, remaining Parmigiano and pancetta.
Cook’s Tip: Fava beans have to be shelled twice! First, remove them from their fuzzy pod as you would any shell bean. Then follow the directions in the recipe to blanch the beans, which have an outer coating around them. Blanching and then submerging the beans in ice-cold water will allow you to slip the coating off. What remains are two bright green halves of the fava bean, which can now take a quick turn in the sauté pan or be used in soups, dips, crostini toppings and more.